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LEKAN
OLATUYI
Research Area of Interest:
Transport and fate of nutrients in soil: quantification and simulation of water and solute movement in agricultural landscape
Postdoctoral Research Study:
Quantitative Relationships between Soil Phosphorus Measures and Subsurface Movement of P in Manitoba Soils
The study examines phosphorus leaching potential using a set of undisturbed soil cores collected from manured field sites in southeastern and southwestern Manitoba. The research study is supported by the Manitoba Department of Water Stewardship, as part of the efforts to understand various pathways of phosphorus loading into Lake Winnipeg’s watershed.
Supervisor: Dr. Don Flaten (Professor)
Ph.D. Research Study:
Measurement and Simulation of Solute Transport in a Hummocky Landscape
Overview:
Within the landscape, there is varying intensity of soil water flow and net downward water flux as controlled by topographic features. It is reasonable to postulate that topographic influence on soil water dynamics within the landscape will also affect the fate and transport of a mobile nutrient such as nitrate, which may consequently degrade the groundwater quality. The magnitude of nitrate movement in the vadose zone is also controlled by a suite of management practices such as N fertilization, soil and cropping systems. However, it is difficult to predict the extent of nitrate movement in agricultural soils due to the complexity of N dynamics. In attempts to enhance our understanding of nitrate movement in particular, and solute transport in general in agricultural landscapes, we employed tracer techniques such as labelled isotope 15N and bromide to investigate effects of landscape variability and N fertility management on vertical and lateral distribution of solute in a hummocky landscape. We also applied mechanistic models known as HYDRUS-1D and HYDRUS-2D/3D to simulate one- and two-dimensional movement of water and solute in the landscape. Knowledge of solute redistribution in the landscape as impacted by N fertility and topographic features, and the ability to predict the fate of nitrate and the associated hydrologic processes, will help to implement management practices for optimizing input resources (fertilizer, pesticide and herbicide), maximizing crop production and reducing groundwater contamination.
Supervisor: Dr. Wole Akinremi (Professor)
M.Sc. Research Study:
Chemical Characterization of Phosphate Diffusion in a Multi-Ionic Environment
Overview:
Problems associated with the efficiency of phosphate fertilizer utilization by crops in calcareous soils are primarily the limited movement of P in the soil-P fertilizer reaction zone. This retarded movement is due to rapid reactivity of the applied P with soil components, more importantly, calcium – which forms a series of insoluble reaction products with P, characterized as residual soil P. These slow-releasing P fractions impede early season plant nutrition of P by lowering the availability of P in soil solution. The continual loading of these less soluble reaction products in soil consequently intensify the risk of P loss to adjacent water bodies through surface and sub-surface pathways, resulting in lake eutrophication. A key strategy for increasing the availability of phosphate ion in calcareous soil is to prevent its tie up by soil calcium either by excluding Ca 2+ from the reaction zone or by lowering the reaction zone pH to preclude Ca-P precipitation or by introducing a competitive anion with P for Ca precipitation. This strategy can be accomplished by modifying the chemical environment of the soil-P fertilizer reaction zone through various nutrients banding with P. Mixing various salts with fertilizer P modifies the chemical environment of the soil-P fertilizer reaction zone, due to induced changes in the pH status and the characteristic interactions of P with soil constituents and other ions. These consequently affect the concentration and movement of phosphate species in the soil solution.
Publications:
Solubility and transport of phosphate and the accompanying ions in a model calcareous soil system; Olatuyi et al. 2009, Can. J. Soil Sci. 89: 589-601
Accompanying cations and anions affect the diffusive transport of phosphate in a model calcareous soil system; Olatuyi et al. 2009, Can. J. Soil Sci. 89: 179-188
Supervisor: Dr. Wole Akinremi (Professor) Previous Degrees :
Ph. D. (Soil Science) University of Manitoba (2011)
M.Sc. (Soil Science) University of Manitoba (2006)
B.Agric (Soil Science) Obafemi Awolowo University, Nigeria (2002)
Email:
umolatuy@cc.umanitoba.ca
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